In their so-called “BLUE” scenario (I haven’t figured out what “BLUE” refers to), a 50% CO2 reduction from 2005 levels by 2050 — what many scientists believe is about what needs to occur to stabilize the climate — is only achievable by tackling emission reductions that have a marginal cost of over $200/ton CO2. Ouch!

Even more provocatively, IEA estimates that the BLUE scenario would imply a widespread move to near-zero carbon buildings and the deployment a billion electric/hydrogen vehicles plus annual investments between 2010 and 2050 of 55 coal plants with carbon sequestration, 32 nuclear plants, 17,500 utility-scale wind turbines, and 215 million square meters of solar panels. By their accounts, this represents $45 trillion of investment above and beyond business as usual.

In IEA’s words, “BLUE is only possible if the whole world participates fully” in shifting to “a completely different energy system.”

Does anyone doubt the magnitude of the CleanTech challenge/opportunity in the coming decades?